The invention relates to improvements in so-called dark boxes, namely to improvements in receptacles or containers from which light or certain other radiation (hereinafter referred to as light) is wholly excluded and which are used to store radiation sensitive photographic and analogous equipment, for example, films, plates and/or paper (hereinafter called light sensitive sheets). Such dark boxes are also called cassettes or magazines.
X-ray equipment is used in many fields including medicine as well as various industries, particularly for nondestructive testing of materials and/or products. Such equipment employs sheets which carry coatings of photosensitive material. When the exposure of a sheet to a required amount of radiation is completed, the thus obtained latent image must be developed in a suitable developing machine. To this end, the exposed but undeveloped sheets are inserted into a dark box within the confines of a darkroom and the dark box is closed and sealed when it receives a desired (e.g., maximum) number of exposed sheets so that the thus closed and sealed dark box can he transported to a developing machine. A dark box which is ready to be relieved of its contents is coupled with a so-called feeder which withdraws discrete sheets, one after the other, and introduces them into the developing machine.
A drawback of presently known dark boxes is that each such receptacle or container is designed to accept exposed sheets of a particular size and shape. Thus, it is necessary to maintain a supply of dark boxes each of which can he used to store exposed sheets of a given size and shape. This contributes to the cost and to space requirements of the equipment, irrespective of whether the sheets are used to receive latent images of parts of human or animal bodies or latent images of inanimate objects in a manufacturing plant or the like. Dark boxes of different sizes are provided with discrete codes which are read by the feeder in order to avoid introduction of sheets into wrong developing machines. In spite of the provision of coded dark boxes, the feeder is likely to make mistakes and to introduce exposed but undeveloped light sensitive sheets into wrong developing machines. Each such error must be corrected (if possible) in a dark room with attendant loses in time, or the sheet which was withdrawn from a dark box is likely to be exposed to light on its way to the developing machine with attendant damage to or total eradication of the latent image. On the other hand, it is normally desirable to rapidly develop the latent images, e.g., in a hospital or in a similar establishment so that the physician or another person in charge can receive an exposed latent image as expeditiously as possible. The same holds true for nondestructive testing of objects in various plants, especially if the results of testing are utilized to modify the operation of various machines in response to detection of unsatisfactory objects.